1. Field of the Invention
The present invention relates to a marking device for making visual permanent markers on surfaces, in particular on walls and/or ceilings and/or floors of constructional structures in accordance with signal markers preset by a surveying or measuring device, e.g., an optoelectronic measuring device, with the marking device including a marking unit, and a detector device that detects the signals emitted by the measuring device and generates a warning signal that the position of the marking unit should be corrected in case the measurement signal emitted by the measuring device deviates from the signal corresponding to a predetermined position of the marker.
2. Description of the Prior Art
The formation of attachment points in constructional elements, housing structures and the like includes essentially measuring, positioning, and visual marking of the attachment points. Then, receiving bores for receiving the desired fastening elements, e. g., anchors, dowels, and/or screws are formed. Also known is a direct setting method according to which a bolt or a similar fastening element is driven into a constructional component, e.g., a concrete wall, with an explosive power charge-operated setting tool. A substantial portion of time necessary for forming such attachment points is devoted to measurements, positioning, and marking. The time and labor expenditures necessary for performing the above-mentioned operations are very large and often exceed those necessary for actual setting of a fastening element. A particular problem arises when the attachments have to be made at a big height as, in this case, as a rule, auxiliary means, such as ladders, platforms, stands and the like, become necessary in order, e.g., to provide a marker on or beneath a ceiling, a wall and to set in a fastening element. If, e.g., an intermediate ceiling need be suspended, the attachment points over the entire ceiling surface should be measured and marked. To this end, a ladder or a platform should be displaced over the entire space, and often the ladder or the platform should be scaled many times. The same applies to mounting of suspended cable lines, tubular conduits and the like.
There exists, however, a number of surveying or measuring, positioning, and marking devices which permit to substantially reduce, in comparison with conventional methods, the time necessary for measuring and marking of the attachment points. In particular, laser technology-based measuring devices, with which a desired position of a fastening element is projected on a surface with a laser ray, are widely used. The laser ray can be periodically rotated and deflected so that lines can also be projected on a surface spaced from a laser measuring device. However, these devices do not permit to provide a fixed, i.e., a permanent marker at a predetermined point or line as, for security reasons, the laser ray power should be kept small. In such devices, as a rule, the laser ray power should not exceed 1 mW, whereas for a direct formation of a visible permanent marker on a wall or a ceiling, a laser ray power of several 100 W is required.
In order to be able to form permanently visual markers with such laser measuring devices, German Patent Publication DE 196 34 800A1 discloses a marking device that is simple in operation and permits to form visible and fixed markers on walls and ceilings. The structure and the operation of the known marking device can be explained with reference to FIG. 1 which shows a perspective view of the marking device 1 disclosed in DE 196 34 800A1.
The marking device 1 has a housing 2 which is preferably formed of a plastic material and is secured on a, preferably, telescopic lance 3. In the embodiment shown in FIG. 1, the lance 3 is connected by articulation means 5 with a support for the housing 2 displaceable on rollers 4. The rollers 4 provide for displacement of the housing 2 along a surface, e.g., wall W. The marking device 1 includes a detector device located behind an entrance window 6 provided in the front wall of the housing 2 for detecting signals emitted by, e.g., an optoelectronic measuring device equipped with a source of a coherent light. The marking device 1 permits to form permanent markers M along a tracer streak L projected onto the wall W by an optoelectronic measuring device (not shown). A control panel 8, which is provided also on the front wall of the housing 2, is used for controlling the operation of the marking device 1. The marking device 1 also includes a pivotal cover 10 (FIG. 2) which is locked in its locking position with a latch 9. Inside the housing 2, a marking unit 19 is arranged (FIG. 2). The marking unit 19 is connected with a container 14, in which a marking fluid is stored under pressure. The marking unit 19 includes a discharge nozzle 15 with an outlet opening 17 and with which markers M are formed on the wall W.
However, the use of the marking device, in particular, its handling is connected with certain problems. As discussed in DE 196 34 800A1, as soon as the entrance window 6 reaches the region of passing of a marker-forming light signal in form of a laser ray emitted by the laser measuring device, the marking device generates an acoustic signal the repetition frequency and/or tone pitch of which indicate(s) to the operator in which direction the marking device should be displaced in order to reach a correct position to provide for forming the visible permanent markers M at correct points on the wall W at which the fastening elements are to be driven in. Provided that the marker is formed at a position which can be easily reached from the floor, the adjustment of the marking device 1 usually does not present a problem, though it is desirable to reduce subsequent adjustments as much as possible. When the marking device is secured, in accordance with a preferred mode of application, on a lance, visible permanent markers can be formed at large heights, in the ceiling region. However, in this case, a subsequent adjustment is much more difficult. With high requirements to the precision of the position of markers M, a subsequent adjustment of a marking device, which is secured on a lance, if at all possible, is connected with an increased time expenditure. In most cases, the adjustment is effected manually by a person staying on a ladder.
Accordingly an object of the present invention is to provide a marking device of the above describe type in which the precise positioning of the marking unit is effected more rapidly than in the known marking device and, preferably, automatically.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing motor means for displacing the marking unit relative to the housing, detector means for detecting the measurement single and for generating a position signal upon deviation of the measurement signal from the marking signal, and control means for controlling the motor means and for actuating same in response to the position signal for displacing the marking unit relative to its reference housing position into a corrected marker-forming position, determined by the marking signal.
Advantageously, the marking process is initiated automatically as soon as the marking unit reaches a correct marking position.
According to the present invention, the control circuit comprises a computer for calculating, based on an impingement position of the marking signal on the detector means, an offset correction signal determining a necessary displacement of the marking unit. In response to the offset correction signal, the motor means correspondingly displaces the marking unit. For displacing the marking unit with respect to its reference position in the housing, the motor means includes an electric linear drive and/or a pivoting drive.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to is construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.